Traditional popcorn popping kettles are provided with electrical heaters for heating unpopped kernels and popping them. The parameters of transfer of heat from the heaters to the kernels through the kettle are significant to the volume and taste of properly popped popcorn.
Previously, heaters have been brazed to the outside surface of a kettle bottom for enhancing conductivity of heat. Heat sensors such as thermostats or other heat sensors are also disposed on the kettle bottom. Once a popping cycle is initiated with energization of the heaters, the heat is conducted to the sensors. The popping control is arranged such that upon a sensed level of heat observed by the sensors, the heat cycle is interrupted so the popped batch can be dumped and new unpopped corn and oil added for another popping cycle.
This prior structure and process is subject to several inherent disadvantages.
For example, the power or wattage density can be so high that the heat from the heater is quickly conducted to the thermostats. They too quickly reach their cycle limit before the kettle surfaces are all appropriately heated for most efficient popping. Thus, high heat limits as sensed by these or other sensors are reached before the actual popping cycle is complete. Early termination of heating results in poor popping of the batch of corn.
For appropriate high quality results, popcorn requires a certain amount of heat for popping. If the sensed temperatures are reached before the sufficient heat has been transferred to the popcorn through the properly heated kettle, the result is incomplete or poor popping, smaller volumes and generally poor results.
Complicating the process is the delay observed, in the first few popping cycles, of the kettle in reaching an “equilibrium” of heat throughout. While a temperature level is set to indicate cycle completion for a kettle having reached equilibrium, that same sensed temperature level observed prior to a kettle reaching an equilibrium may not indicate that sufficient heat has been imparted to the load of popcorn for efficient popping.
This occurs, for example, when a kettle is first turned on, as with a first batch. Heat may be more quickly conducted to the heat sensors at a rate quicker than the time required for the kettle to reach an equilibrium. Since the heated kettle at equilibrium more efficiently transfers heat for popping, the sensing of a temperature level for a kettle upon a first or cold start may not be optimum for indicating the end of an efficient popping cycle for the first or first several cycles.
Accordingly, it has been one objective to provide an improved popping kettle in which the sensed heat level for the first cycle of popped corn is an accurate indication of efficient cycle completion.
Another objective of the invention has been to provide an improved popping kettle where sensed heat by a heat sensor in a first cycle does not prematurely indicate completion of popping for the first cycle.
Another objective of the invention has been to provide an improved popping kettle with improved heater and heat sensor mounting structure.
To these ends, a preferred embodiment of the invention comprises a popcorn kettle with a heater plate secured to a kettle bottom with heaters and thermostats mounted on the plate. A pattern of semicircular slots is provided in the plate, such that slots are oriented in the plate between the heaters and the thermostats. Ends of the slots define therebetween heat conduction paths between the heaters and thermostat, but the paths or conduction areas represent only limited conduction areas as compared to a plate without any slots or discontinuities between the heaters and the thermostat. These slots are sufficient to diminish the initial conduction of heat to the thermostats and thus reduce the rate of initial thermal saturation of the thermostats to a degree sufficient to allow even the first batch of corn to finish popping.
Heat conductivity to the thermostats is thus delayed sufficiently so the thermostats do not prematurely reach their set levels to indicate completion of a popping cycle before sufficient heat has been transferred to the load of corn for efficient popping.
This structure allows the kettle to reach more of an “equilibrium” of heat during even the first batch of popping so that too quick conduction of heat to the thermostats does not prematurely end a popping cycle.
Thus, the invention contemplates an improved popcorn popping kettle wherein heaters are mounted to the kettle via a heat plate provided with predetermined structurally restricted heat conduction pathways between the heaters and heat sensing thermostats to prevent premature cessation of popping due to rate of heat rise and the thermostat.
These and other objects and advantages will be readily appreciated from the following written description and from the drawings in which: